Yet the sources of funding behind these good-government groups' own work can be murky.

Tax and other records that are available show occasional connections to donors that might bring questions from the watchdogs if different players were involved, or if the same fact-pattern concerned a state lawmaker's campaign donations.

The targets of good-government groups have leveled such criticisms: During his 2010 State of the State address, former Gov. David Paterson memorably proposed creating an independent ethics commission with oversight of "so-called good government groups, who hide their donors behind walls of sanctimony."

Paterson's proposal came after NYPIRG's Horner had helped spur a probe into the governor's solicitation of Yankees World Series tickets.

Often on shoestring budgets, media savvy allows the groups to punch above their weight, and many observers of state-government deem their efforts laudable.

The bulk of their funds come from small grassroots donations and foundations, but that's not always the case.

The state League of Women Voters has taken five-figure sums from the state teachers union, and also fought for its causes. Citizens Union and Common Cause both took grants from a key faction of the labor-backed Working Families Party that funded studies meant to promote publicly funded elections, a top labor priority.

NYPIRG has been accused by Gov. Andrew Cuomo's administration of being a "mouthpiece" for the trial lawyers' lobby, and did give a grant to an anti-tort reform group in 2011, records show. Some of NYPIRG's donors are unknown because of a sudden shift in the group's lobbying spending in 2012 as a new disclosure law came into being — timing that Horner said is a coincidence.

Indeed, not much information is available concerning the good-government groups' backers on the website of the state's lobbying regulator, the Joint Commission on Public Ethics (JCOPE).

Only Citizens Union discloses the donors that fund its lobbying; the other three groups say they do not currently meet the requirements forcing disclosure.

Federal Department of Labor filings, however, show in 2014 the state League of Women Voters received more than $18,000 from the New York State United Teachers, a powerful labor union, and has received other five-figure donations from the union in the past.

The league has supported NYSUT issues before the Legislature.

In 2011, the group fought against Cuomo's proposed property tax cap, which the union contends chokes off school funding.

The league's legislative director Barbara Bartoletti organized a news conference in 2014, and participated in another in 2015, slamming a private education tax credit opposed by the teachers union.

"It shouldn't come as a surprise that we would support an organization that agrees with us, including on issues before the Legislature," NYSUT spokesman Carl Korn told the Times Union.

But the league's executive director, Laura Ladd Bierman, said NYSUT funds went not to lobbying efforts, but to its annual Students Inside Albany Conference, a four-day seminar for high school students.

"Any position or advocacy taken by the League of Women Voters of NYS is permitted only through member research, study and support," Bierman said via email. "The league can only lobby on issues adopted by its members."

The donors to league's charitable arm are published and posted on its website annually, a level of disclosure that goes beyond what's required by law. Besides NYSUT, another major statewide public sector union, CSEA, also gave more than $5,000 in 2014-2015 to the league, according to the website. Hundreds of smaller individual donors are also listed.

Two other New York good-government groups, Common Cause (a national organization based in Washington D.C.) and Citizens Union (which started as a New York political party that once fought Tammany Hall), have taken money from a group closely within the orbit of NYSUT.

Tax records from 2013 show Common Cause got $50,000 and Citizens Union received $15,000 in "sub-grants" from an Albany nonprofit called Public Policy Education Fund of New York.

Instead of going to their more political arms, the money benefited their charitable, educational arms, and therefore did not have to be disclosed to JCOPE.

The Education Fund is the nonprofit research and public education affiliate of Citizen Action, which has a political action committee that works to support Democratic takeover of the state Senate, and is a key player in the labor-backed Working Families Party.

NYSUT's 2015 filing with the federal Department of Labor says it gave $210,000 last year alone to the Education Fund.

Karen Scharff, one of the state Capitol's most ubiquitous liberal activists, runs both the Education Fund and Citizen Action.

According to Scharff, the grant money raised by the Education Fund came from a number of foundations as well as from Jonathan Soros, the son of the hedge fund billionaire George Soros, one of the nation's biggest liberal political spenders.

Jonathan Soros — whom Scharff estimated had given $50,000 to the Education Fund's efforts at the time — has himself spent heavily recent election cycles seeking to win Democratic control of the state Senate.

The money raised by the Education Fund was then directed to Common Cause, Citizens Union and a number of other groups as part of a 2013 push for publicly funded elections, which many believe would help Senate Democrats' electoral odds.

For the good-government groups, the money was intended to fund reports critiquing the influence of big money in New York elections. Notably, Common Cause and Citizens Union favored publicly funded elections long before this funding materialized.

Asked if Common Cause or Citizens Union would have the freedom to slam labor unions or a liberal billionaire like George Soros — themselves huge political spenders — Scharff said, "We definitely don't tell them how to write their reports, but we do give them funding to advance the goals and priorities of the campaign finance reform effort."

In the resulting reports, neither Common Cause nor Citizens Union disclosed that the Education Fund was the donor who provided their funding, although it was well-publicized they were all working together on the publicly funded elections campaign.

With its money, Common Cause funded "Moreland Monday" studies asking the then-operating Moreland Commission on Public Corruption to examine spending by real estate, gambling, pharmaceutical and hydrofracking industries. (Citizen Action, notably, is strongly opposed to fracking). One study — on the abuse of "housekeeping accounts" — did question political spending by the health care workers union 1199 SEIU, a close ally of Citizen Action, along with that of a number of corporate interests.

Common Cause executive director Susan Lerner said her organizations' even-handedness has scared away potential donors in the past. "The truth of the matter is (donors) don't expect to dictate the result of a report," Lerner said. "We have to maintain independence and credibility."

As for Citizens Union, Executive Director Dick Dadey said the Education Fund's money supported two reports: one examining the undisclosed spending of New York political clubs, the other pushing publicly funded elections and campaign finance reform.

Citizens Union has gained a reputation as a centrist group and has maintained closer ties to some politicians, including the governor. This has brought criticism from some quarters that the group's critical voice has been muted. Dadey said the intent is simply to work constructively with government.

Citizens Union has taken the most proactive approach toward disclosing lobbying donors.

JCOPE requires the disclosure of gifts greater than $5,000. Dadey said that even if only a small fraction of such a donation is used for lobbying, the donor's name is listed by Citizens Union in filings.

"We probably over-report, but we want to be safe and secure," Dadey said. "You can't criticize someone unless you're in full compliance."

Among the donors listed are major New York City real estate players (the Durst Organization, Tishman Speyer) and influential lobbyists such as James Capalino.

"No donor has ever called me up to ask us to take a position on any of their issues," Dadey said.

A shift in policy by NYPRIG has meant that donors behind its lobbying spending aren't disclosed to JCOPE, a result Horner insisted was coincidental.

In 2011, with the strong support of these good-government groups, the Legislature passed a law requiring issue-oriented nonprofits — designated as 501(c)4 groups — spending more than $50,000 annually on lobbying to disclose donors of more than $5,000.

In 2009, 2010 and 2011, NYPIRG's issue-oriented nonprofit — a 501(c)4 that would have to disclose its donors under the new law — spent $114,000, $125,000 and $67,000, respectively.

Since the disclosure law took effect in 2012, however, NYPIRG's lobbying spending through the 501(c)4 has dipped considerably. In 2012, it went slightly below the $50,000 mark and has gone further below that threshold since.

At the same time, spending has spiked out of a different nonprofit arm sharing the same Manhattan address, the NYPIRG Fund, a type of apolitical, charitable nonprofit designated as a 501(c)3. Spending from the NYPIRG Fund grew from about $12,000 in 2011 before the disclosure law took effect to $54,000 in 2012. The NYPIRG Fund's annual spending has remained around that level every year since, and was close to again hitting the $50,000 threshold for 2015.

But the NYPRIG Fund won't have to disclose the donors funding its lobbying: The 2011 lobbying reform does not apply to such apolitical 501(c)3 charities. On its face, the shift in spending is odd: Such charities, which can take tax-deductible donations, face strict limits from the Internal Revenue Service on the levels of their lobbying spending.

Horner said the change was not meant to obscure NYPIRG's donors, but was a result in a shift in priorities by the 501(c)4's board of directors, which is made up of college students.

The 501(c)4 is funded by student activity fees, and the leadership wanted to spend more on activities on college campuses, Horner said.

That meant the lobbying spending had to be picked up by the 501(c)3. "The net effect was more money on college campuses," he said.

In 2011, a spokesman for Cuomo called Horner "a mouthpiece for the trial lawyers" after he criticized the governor's plan to cap awards in medical malpractice lawsuits. Horner wrote a letter to the Times Union in 2014 in defense of the state's Scaffold Law, which is supported by the trial lawyers' lobby.

Tax records show that in 2011, the NYPIRG Fund gave a nearly $12,000 grant for "general support" to the Center for Justice and Democracy, a nonprofit that according to its website works to "fight tort reform," including in New York. Horner said he was not sure of the reason for the NYPIRG Fund's gift, but said as far as he knew neither the state Trial Lawyers Association nor the Academy of Trial Lawyers had donated to NYPIRG for many years.

Horner, for many one of the Capitol's more deeply respected figures, said he would likely be supportive if a new state law were proposed requiring 501(c)3 groups to disclose large donors.

As for whether good-government groups asking for transparency from lawmakers could lead by example by disclosing their donors voluntarily, Horner declined to identify all the financial supporters of his group, because they had donated with the expectation of privacy.

"There's a difference," Horner added, "between people who make laws and people who don't."